The present invention is directed generally to a fluid flow system, and more particularly to a pre-sterilized disposable flow system for processing blood and other biological cells while under centrifugation which does not utilize a rotating seal member.
In recent years long term storage of human blood has been accomplished by separating out the plasma component of the blood and freezing the remaining red blood cell component in a liquid medium such as glycerol. Prior to use, the glycerolized red blood cells are thawed and pumped into a centrifugating wash chamber where, while being held in place by centrifugation, they are washed with a saline solution which displaced the glycerol preservative. The resulting reconstituted blood is then removed from the wash chamber and packaged for use.
The aforedescribed blood conditioning process necessitates the transfer of glycerolized cell and saline wash solutions into the wash chamber, and the transfer of glycerol waste and reconstituted blood from the wash chamber, while the chamber is in motion.. To avoid contamination of the blood or the exposure of persons involved in the processing operation to infection these fluid transfer operations must be carried out within a sealed pre-sterilized flow system, preferably formed of a flexible plastic or similar material which can be disposed of after each use.
One drawback present in many such flow systems has been their use of a rotating seal or coupling element between that portion of the system carried by the centrifuge rotor and that portion of the system which remains stationary. While such rotating seals have provided generally satisfactory performance, they have been expensive to manufacture and have unnecessarily added to the cost of the flow systems. Furthermore, such rotating seals do introduce an additional component into the system which if defective can cause contamination of the blood being processed. This is particularly true when two different batches of blood are being simultaneously processed since the components of one blood batch must pass side-by-side through the rotating seal with the components of another blood batch.
One flow system heretofore contemplated to overcome the problem of the rotating seal utilizes a rotating carriage on which a single housing is rotatably mounted. An umbilical cable extending to the housing from a stationary point imparts planetary motion to the housing and thus prevents the cable from twisting. To enable fluid to be centrifugally processed an inner wash chamber is rotatably mounted within the housing and connected to the umbilical cable by a rotating seal. A weight on the chamber causes the chamber to be radially aligned as the rotor turns to maintain a constant centrifugal force field on the fluid. Unfortunately, this arrangement requires the use of an expensive and trouble-prone rotating seal, albeit in the housing, and allows the use of only one wash chamber, preventing the simultaneous processing of multiple batches of cells.
Thus the need exists for a centrifugal cell processing system wherein multiple batches of cells can be simultaneously and efficiently processed without the use of rotational coupling elements. In the co-pending application of the present applicant, Ser. No. 657,187, filed Feb. 11, 1976, a continuation-in-part of application Ser. No. 562,748, filed Mar. 27, 1975 and assigned to the present assignee, a centrifugal cell processing system and apparatus are described which encompass the principle of operation of apparatus described in U.S. Pat. No. 3,586,413 to Dale A. Adams, and which avoid the use of rotary coupling elements. The present invention is directed to a disposable flow system for use in that system.